Question

The pressure of a mixture of equal weights of two gases $X$ and $Y$ with molecular weight $4$ and $40$ respectively is $1.1atm$. The partial pressure of the gas $X$ in the mixture is :

• A. $1atm$
• B. $0.1atm$
• C. $0.15atm$
• D. $0.5atm$

Answer 1

The correct option is A $1atm$

Let $wg$ of each gas is taken.
Mole fraction of $X=\frac{\frac{w}{4}}{\frac{w}{4}+\frac{w}{40}}=\frac{10}{11}$
Partial pressure of $X=P_{total}\times Molefraction$
$=1.1\times \frac{10}{11}=1atm$.